JPH063395B2 - Analyzer with liquid level detection function - Google Patents

Description

TECHNICAL FIELD The present invention relates to an analyzer having a liquid level detection function, and more particularly to detecting a liquid level from a change in capacitance when a dispensing probe comes into contact with the liquid level. To a possible analyzer.

[Conventional technology]

JP-A-57-82769 is known as an example in which a liquid level probe is provided in a liquid dispensing probe of an automatic clinical analyzer.
In this example, the dispensing probe equipped with the liquid level sensor is lowered toward the liquid surface of the reagent container, and the container for the reagent liquid remaining in the reagent container from the descending distance until the liquid level sensor reaches the liquid surface. Is configured to calculate.

In this Japanese Patent Laid-Open No. 57-82769, a pair of electrodes, a dispensing probe electrode and a liquid level detecting electrode, move up and down as a unit, so that it can be placed in a liquid container equipped with a film lid for preventing evaporation of reagents and the like. It was inconvenient when inserting. Therefore, it has been attempted to apply the capacitance type liquid level sensor to an automatic analyzer.

Dispensing a fixed amount of liquid with a probe after detecting the liquid level using capacitance is known from US Pat. No. 3635094, but in this conventional technique, a probe and a liquid level detection electrode are used. Since it is separately provided, it has been attempted to use the probe itself as a liquid level detection electrode.

JP-A-62-194464 is known as a recent example of application of a capacitance type liquid level sensor to an automatic analyzer. In this example, it is shown that the liquid in the container provided with the membrane lid is dispensed by the probe in which the liquid level sensor electrode and the liquid suction / discharge tube are integrated. In this example, the residual liquid amount in the container is calculated based on the height of the container itself and the moving distance of the probe at a constant speed.

[Problems to be Solved by the Invention]

When measuring the capacitance between the probe that also serves as the liquid level sensor and the counter electrode provided below the liquid container, applying a high-frequency signal to the probe generates radio waves that affect the operation of other devices. There was a problem. The above-mentioned JP-A-62
-194464 does not consider such problems.

When attempting to detect the liquid level in a liquid storage container equipped with a liquid evaporation prevention film lid using a dispensing probe that also serves as the liquid level sensor electrode, the probe will be attached to the film lid when the probe is inserted into or removed from the container. Often comes into contact. For example, when the reagent solution container has a membrane lid, the reagent solution attached to the outer wall of the probe adheres to the membrane lid when the probe is pulled out from the container. There is no problem if the reagent solution is dispensed only once,
There is a problem that the presence of a slight amount of reagent liquid adhering to the membrane lid is erroneously detected as the liquid surface during the second and subsequent dispensing. The aforementioned Japanese Patent Laid-Open No. 62-194464 does not consider such a problem.

A first object of the present invention is to provide an analyzer having a liquid level detection function that can reduce the generation of interference radio waves to other devices during liquid dispensing by a probe.

A second object of the present invention is to provide an analyzer having a liquid level detecting function capable of surely detecting the liquid level in the liquid container even when the liquid adheres to the container film lid.

A third object of the present invention is to provide an analyzer having a liquid level detecting function capable of detecting the liquid level in a container with a simple configuration regardless of whether the liquid container has a film lid or not. It is in.

[Means for Solving the Problems]

The present invention is configured so that the dispensing probe detects the liquid surface by a change in capacitance when the dispensing probe comes into contact with the liquid in the liquid storage container, and an oscillating unit that gives a high-frequency signal to the probe is provided,
The probe is characterized by having an oscillation control unit that starts high-frequency oscillation from the oscillation unit when the probe moves downward and approaches the upper end of the liquid container, and stops high-frequency oscillation when the probe reaches the liquid surface. To do.

When the liquid container has a membrane lid, the capacitance value when the tip of the probe is located between the membrane lid and the liquid surface and the capacitance value when the tip of the probe contacts the liquid surface are described. Configured to detect.

Further, in a preferred embodiment of the present invention, an electrode plate capable of mounting a plurality of liquid storage containers is provided, and a reagent solution container having a membrane lid and a sample container having no membrane lid are mounted on the electrode plate. When the reagent solution and the sample are dispensed into the reaction container by the same probe, the probe detects the reagent liquid surface in the reagent liquid container and the sample liquid surface in the sample container.

[Action]

Even if a high-frequency signal is applied to the probe electrode held by a holding means such as a rotating arm, the influence of interference radio waves on other devices is relatively small while the probe electrode is inserted into the container. In the present invention, it is noted that it is necessary to detect the liquid level in the liquid storage container below the upper end of the liquid storage container, and after the probe starts the descending motion and reaches a position slightly above the upper end of the container. The generation of interfering radio waves is reduced by giving high frequency only.

When the container is equipped with a membrane lid, the base preparation value control signal is output before the probe reaches the membrane lid, and the probe tip is moved downward from the membrane lid to reach the liquid level. The capacitance value is stored as a reference value. When the liquid is attached to the membrane lid, the capacitance value will change significantly if the probe outer wall contacts the membrane lid, but the probe outer wall is in contact with the membrane lid until the probe tip reaches the liquid surface. Continue. However, since the amount of liquid adhering to the membrane lid is extremely small compared to the amount of liquid contained in the container, the capacitance value when the probe tip reaches the liquid level and the above-mentioned reference capacitance The difference from the value can be recognized.

〔Example〕

In a preferred embodiment of the present invention, a set electrode for grounding the liquid container, a metal probe electrode that can be inserted into the container, and a capacitance value between both electrodes connected to each electrode are provided. Capacitance value detecting means for outputting a signal, output means for outputting a reference value control signal, reference value storing means for storing the output of the capacitance detecting means at the time of signal generation as a reference value by the reference value control signal, A liquid level that compares the reference value stored by the reference value storage means with the output of the capacitance detection means, and outputs a liquid level detection signal when the output of the capacitance detection means exceeds the reference value. It has a position detection means and an oscillation control means for controlling the generation of an obstacle radio wave during the liquid level detection operation.

An embodiment of the present invention will be described with reference to FIGS.

The disk 8 in FIG. 2 is rotated by a known driving device and positioned at a predetermined angle. A metal plate 9 is arranged on the bottom of the disk 8 almost all over and is grounded. This metal plate functions as one electrode of the liquid level detection device.
A large number of sample containers 7 are arranged on the inner peripheral side of the disk 8.
A plurality of reagent containers 6 are arranged on the outer peripheral side according to the analysis item to be inspected. Since the sample container 7 containing the blood sample and the reagent container 6 containing the reagent solution for reaction are different in size, the upper end height of the sample container 7 and the upper end height of the reagent container 6 are the same on the bottom metal plate. Are formed in different steps.

On the upper end of the reagent container 6, a plastic film 15 as a film lid is stretched as shown in FIG. In this example, the membrane lid is not attached to the upper end of the sample container 7, but a membrane lid may be provided. On the other hand, on the reaction disk 2 in FIG. 2, cuvettes 1 as reaction vessels are arranged along the circumference. Near the row of reaction vessels,
A cleaning mechanism 41 for cleaning the cuvette 1 is provided, and a photometer (not shown) for irradiating the cuvette with light to measure fluorescence from the reaction solution in the cuvette is provided. The reaction disk 2 is intermittently rotated by a well-known drive device.

The blood sample in the sample container 7 and the reagent solution in the reagent container 6 are dispensed into the reaction container 1 on the reaction disk 2 by the sampling mechanism 42 when they are positioned at predetermined suction positions. The spline shaft of the sampling mechanism 42 is vertically moved and rotated by the sampling arm drive device 37. A control signal is applied to the pulse motor of the drive unit 37 from the sampling arm unit control unit 38. An arm 5 is fixed to the spline shaft 10, and a probe electrode 4 made of a metal pipe is held by the arm 5 via an insulating material 3.

As shown in FIG. 1, the spline shaft 10 is provided with a detection plate 14 capable of blocking light across the photo interrupter 19 for a predetermined time width while the probe electrode 4 is moving downward. ing. A reference value control signal is generated while the detection plate 14 is passing through the photo interrupter 19. The probe electrode 4 is a tube 12, a solenoid valve 11
Solenoid valve 16, connected via a syringe 13
It is connected to the tube 17. The end of the tube 17 is inserted into a container 21 that contains a chase liquid (pure water) 18. The metal probe electrode 4 is connected via a lead wire 20 to a capacitance detection circuit 25, which will be described later, as capacitance detection means.

Since the probe electrode 4 also serves as a liquid suction / discharge tube and one electrode as a liquid level sensor, the probe 4 rotates and moves up and down in accordance with the operation of the sampling mechanism, and a fixed amount of the sample in the sample container 7 is obtained. Is discharged to the reaction container 1 and a fixed amount of the reagent liquid in the reagent liquid container 6 is discharged to the reaction container 1. With the operation of dispensing the liquid in the sample container 7 and the reagent liquid container 6, the probe 4 detects the liquid level in each container.

Next, the liquid level detection operation will be described.

As shown in FIG. 3, the electrostatic capacitance detection circuit 25 includes an oscillation circuit 22, a differentiation circuit 23, and a rectification circuit 24, and the differentiation circuit 23 is connected to the metal probe electrode 4 via the lead wire 20. The rectifier circuit 24 is connected to the liquid level detection determination circuit 26.

A case where the liquid container is provided with a membrane lid will be described with reference to FIGS. 4 to 10. FIG. 4 shows the static distance between the probe electrode 4 and the metal plate 9 with respect to the distance between the metal probe electrode 4 and the metal plate 9 when the upper part of the reagent container 6 is covered with the plastic film 15 as shown in FIG. The change in capacitance is shown. And FIG. 5 has shown the structure at the time of the characteristic measurement of FIG. In FIG. 5, the distance from the metal plate 9 when the probe electrode 4 descends and comes into contact with the film 15 is x.
_{2. If} the distance from the metal plate 9 when it further descends and comes into contact with the liquid surface in the reagent container 6 is x ₁ , the capacitance (c) value is x.
It changes in two stages: ₂ position and x ₁ position. Further, x ₁ position when liquid adheres to the film 15, and x ₂ the position results in variations in such an electrostatic capacitance (c) value indicated by the shaded portion, the static of x ₂ about positions x ₁ position Electric capacity (c)
It is also possible to get. Therefore, it is impossible to detect the liquid level by a method of setting a constant capacitance as a reference value and lowering the probe electrode 4 from the upper portion of the reagent container 6.

In this example, the capacitance value when the probe electrode 4 is in contact with the film 15 (x ₂ ) is used as a reference value, and the probe electrode 4
Accurately detects the liquid level by a stepwise liquid level detection method that detects a capacitance change when the liquid level contacts (x ₁ ). That is, when the probe 4 descends and the tip of the probe comes into contact with the liquid surface of the reagent in the container, the capacitance value at this time exceeds the above-mentioned reference value by several tens of mV (100 μ of pure water is stored in the container. If).

Next, the capacitance detection circuit 25 will be described. As shown in FIG. 6, the oscillator circuit 22 is configured to output a pulse signal of a constant cycle to the differentiating circuit 23. The oscillation circuit 22 is controlled to turn on / off the oscillation by the liquid level detection signal 28 and the EOR gate signal of the reference value control signal 27. Since the oscillation frequency of the oscillation circuit 22 is as high as 100 KHz (kilohertz), there is a possibility that an interfering radio wave will be generated from the probe electrode 4. In this example,
By controlling the on / off of the oscillation circuit 22 according to the descending operation of the probe 4, the interference radio wave generated from the probe electrode 4 to other devices is reduced. 22A and 22C are flip-flops.

Next, the differentiating circuit 23 uses the resistors 23A, 23B, 23C, 2
3D, capacitors 23E and 23F, and an operational amplifier 23G, the positive terminal of the operational amplifier 23G is connected to the oscillation circuit 22 via the resistor 23A, the earth line is connected to the metal plate 9, and the negative terminal is connected to the lead wire 20. It is connected to the probe electrode 4.

The differentiation circuit 23 is configured to differentiate the pulse signal from the oscillation circuit 22 according to the capacitance value between the metal plate 9 and the metal probe electrode 4, and output the differentiated signal to the rectification circuit 24. . When the probe 4 is in the non-contact state a with the sample in the reagent container 6, the capacitance between the metal plate 9 and the probe electrode 4 is about several fF (1fF is 10 ⁻¹⁵ farad).
Therefore, a signal as indicated by the characteristic a in FIG. 7 is output. The rectifier circuit 24 includes a diode 24A and a capacitor 2
4B and a resistor 24C, and a differentiating circuit 23
When the signal of the characteristic a in Fig. 7 (b) is received from
The signal indicated by the characteristic a in FIG.

When the probe electrode 4 comes into contact with the film 15 on the reagent container 6, the capacitance between the metal plate 9 and the probe electrode 4 changes to about several hundred fF, so that the output voltage of the differentiating circuit 23 increases by several mV. , And outputs the signal represented by the characteristic b in FIG.

Furthermore, when the probe electrode 4 comes into contact with the reagent liquid surface in the reagent container 6, the capacitance between the metal plate 9 and the probe electrode 4 changes to several pF (1 pF is 10 ⁻¹² farad). The output voltage of the differentiating circuit 23 increases by several tens of mV, and the signal shown by the characteristic c in FIG. 7B is output. When the signal having the characteristic b in FIG. 7B is received from the differentiating circuit 23, the rectifying circuit 2
4 outputs the signal indicated by the characteristic b in FIG. 7 (c), and when the signal of the characteristic c in FIG. 7 (b) is received from the differentiating circuit 23, the rectifying circuit 24 causes the rectifier circuit 24 in FIG. The signal represented by the characteristic c is output. In this way, the rectifier circuit is the differentiation circuit 23.
It is configured to output a signal according to the level of the differential value of.

The liquid level detection / determination circuit 26 of FIG. 3 has a circuit corresponding to the reagent container 6 provided with a membrane lid and a circuit corresponding to the sample container 7 having no membrane lid. One of the two circuits is selected according to the inhalation position corresponding to each container.

The liquid level detection determination circuit 26 when the upper portion of the reagent container 6 is covered with the film 15 is composed of resistors 26A, 26B and 26C, a capacitor 26D, an analog switch 26H and a comparator 26E as shown in FIG. The output voltage Vc of the capacitance detection circuit 25 is applied from the terminal 26F, and the liquid level detection signal 28 is output from the terminal 26G. The analog switch 26H has a reference value control signal 27.
The capacitor 26D serves as the reference value setting means and opens and closes the contact according to the comparator 26.
E is configured as a liquid level detecting means.

The reference value control signal 27 is supplied from the film 15 of the reagent container 6 from a position 3-5 mm above the upper end of the reagent container 6 in which the tip of the probe electrode 4 covers the upper part of the container with the film 15 in the vertical movement range of the probe electrode 4. A signal is generated at a position of 3 to 5 mm below and in a range where the tip of the probe electrode 4 is not in contact with the reagent solution in the reagent container 6.

Next, the operation when detecting the liquid level with respect to the reagent container will be described.

When the probe 4 descends and reaches a position 3-5 mm above the film surface stretched on the upper end of the reagent container 6, the detection plate 14 begins to enter the photo interrupter 19. Accordingly, the photo interrupter 19 becomes a reference. The generation of the value control signal 27 is started. As shown in FIGS. 6 and 9, in the oscillation circuit 22, the flip-flop 22C detects the rising of the reference value control signal 27, generates the oscillation circuit output voltage, and simultaneously closes the analog switch 26H in FIG.
The output voltage Vc of the capacitance detection circuit 25
Charge D. This charging voltage is divided by the resistors 26A and 26B so as to be higher than the voltage applied to the negative terminal of the comparator 26E by about 10 mV and then applied.

When the probe electrode 4 continues descending and the tip of the probe electrode 4 reaches a position 3-5 mm below the film 15 covering the upper part of the reagent container 6, the detection plate 14 causes the photo interrupter 19 to move.
Since the reference value control signal 27 is no longer output because it has passed through the detection range of the photo interrupter 19 and the analog switch 26H is opened, the capacitance detection circuit 25 in the same state is set as the reference voltage in the capacitor 26D,
The reference voltage is maintained during the discharging time of the capacitor 26D.

When the probe electrode 4 further descends within the discharge time of the capacitor 26D and the tip of the probe electrode 4 comes into contact with the sample in the reagent container 6, the output voltage Vc of the capacitance detection circuit 25 is several tens m.
V rises and the voltage at the negative terminal of the comparator 26E becomes higher than the reference voltage discharged from the capacitor 26D. Therefore, an "L" level signal is output from the terminal 26G as the liquid level detection signal 28, and at the same time, in the oscillation circuit 22, the flip-flop 22A detects the trailing edge of the liquid level detection signal 28 and the oscillation is stopped.

If the descending motion of the probe 4 is stopped as soon as the probe 4 contacts the surface of the reagent liquid surface in the reagent container,
It is not possible to inhale a predetermined amount of reagent solution into the inside. Therefore, in this embodiment, the sampling arm controller 3
In FIG. 8, a delay time t of a predetermined length is added to the liquid level detection signal 28, and the probe electrode 4 is further lowered by a predetermined film separation even after the liquid level detection signal 28 is generated, so that the tip of the probe electrode 4 is moved. It is possible to reliably enter the liquid surface in the reagent container 6.

Further, as an applied operation in the liquid level detection determination circuit 26,
Detecting a change in the output voltage of the capacitance detection circuit 25 when the metal probe electrode 4 comes into contact with the film 15 on the reagent container 6 by reversing the logic of the stop control signal 27 to the analog switch 26H. Therefore, the probe electrode 4 can be stopped at the contact position of the film 15 on the reagent container 6.

FIG. 10 is a flowchart showing the operation of the liquid level detection determination circuit of FIG.

Next, a case where the liquid level detection determination circuit 26 of FIG. 3 performs the liquid level detection operation for the sample container 7 having no film lid will be described. When the probe 4 is positioned on the sample container row, the liquid level detection determination circuit 26 changes from the circuit of FIG.
The circuit is switched to the one shown in FIG.

FIG. 12 illustrates the operation of the probe during such liquid level detection, and FIG. 11 shows the relationship between the movement of the probe with respect to the sample container 7 having no membrane lid and the change in capacitance. . When the distance from the metal plate 9 when the probe 4 descends and comes into contact with the liquid surface in the sample container 7 is x ₁ , the capacitance (c) value changes rapidly only at the x ₁ position. In this case, the liquid level can be detected by setting the capacitance detection voltage 29 when the tip of the probe electrode 4 contacts the liquid surface in the sample container 7 as the reference voltage (first). (See Figure 14).

The liquid level detection determination circuit 26 in the case where the upper portion of the sample container 7 is not covered with the sealing material is, as shown in FIG. 13, resistors 36J, 36K, 36L, 36M and a capacitor 36.
N, a comparator 36Q, and a terminal 36
The output voltage 29 of the capacitance detection circuit 25 is applied from I,
The liquid level detection signal 32 is output from the terminal 36P. The probe 4 starts the descending operation, and the photo interrupter 19 is moved from a position 3 to 5 mm above the sample container 7.
Are the same in that they detect the detection plate 14 and generate the reference value control signal 27. Along with this, in the oscillation circuit 22, the flip-flop 22C causes the reference value control signal 27 to rise.
Detects and starts oscillating. A capacitance detection circuit output voltage is applied to the plus terminal of the comparator 36Q via the resistor 36M and the capacitor 36N, and a capacitance detection circuit lower than the plus terminal by about 10 mV by the resistors 36J and 36K to the minus terminal of the comparator 36Q. Output voltage 29
Is applied through the resistor 36L.

When the probe electrode 4 continues to descend further and the tip of the probe electrode 4 comes into contact with the sample liquid surface in the sample container 7, the output voltage 29 of the capacitance detection circuit 25 increases by several tens of mV. A resistor 36M and a capacitor 3 are connected to the positive terminal of the comparator 36Q.
Since 6N gives a time constant of about 0.1 seconds,
Before the input voltage 30 to the positive terminal of the comparator 36Q rises by tens of mV, the input voltage to the negative terminal of the comparator 36Q rises by tens of mV. Therefore, since the input voltage 31 to the negative terminal of the comparator 36Q becomes higher than the input voltage 30 to the positive terminal, an "L" level signal is output from the terminal 36P as the liquid level detection signal 32, and at the same time, the oscillation circuit 22. Then, the flip-flop 22A detects the trailing edge of the liquid level detection signal 28 and stops the oscillation.

As shown in FIG. 14, by adding a delay time t of a predetermined length to the liquid level detection signal 32 by the sampling arm unit control device 38 (FIG. 1) and fetching the signal,
The tip of the probe 4 can be stopped by penetrating the sample container 7 slightly below the sample surface.

Another embodiment of the present invention will be described with reference to FIGS. 15 and 16. This embodiment has the same structure as that of the previous embodiment except for the liquid level detection / determination circuit 26 shown in FIG. The liquid level detection determination circuit in this embodiment can detect the liquid level regardless of the presence or absence of the film. That is, as shown in FIG. 15, the liquid level detection determination circuit includes an A / D converter 26S, a data latch unit 26R, and a RAM 26.
The output voltage 33 of the electrostatic capacitance detection circuit 25 is applied from the terminal 26Q, and the liquid level detection signal 39 is output from the terminal 26W. Is configured to.

In the comparison / determination unit 26U, the change characteristics of the capacitance detection circuit output voltage 33 when there is a film on the container upper part and the capacitance detection circuit output voltage 33 when there is no film on the container upper part
Of the change characteristics, and a program capable of detecting the liquid level at the time of the two characteristics is incorporated in the single-chip computer 26X. The distinction between the two characteristics is made by inputting the identification signal 26Y into the single chip computer 26X.

Next, the operation when detecting the liquid level will be described. The probe electrode 4 is vertically driven by the sampling arm driving device 37, and its operation is controlled by the sampling arm unit controller 38.

When the probe electrode 4 descends, the identification signal 26Y is input to the single-chip computer 26X to determine the presence / absence of the sealant on the upper part of the container, and the comparison / determination unit 26U selects the characteristic change when the sealant is present.

The photo interrupter 19 from a position 3 to 5 mm above the container
Detects the detection plate 14 and generates a reference value control signal, and the oscillation circuit 22 detects the rising of the reference value control signal 27 by the flip-flop 22C and starts oscillation. A / D at the same time
The converter 26S converts the electrostatic capacitance detection circuit output voltage 33 into a digital signal in synchronization with the clock signal 26V, and stores the output signal of the A / D converter 26S as a reference value in the data latch unit 26R. On the other hand, RAM26T
The output signal of the A / D converter 26S is sequentially stored in.

When the upper end of the liquid container is covered with the seal material, the capacitance detection circuit output voltage 33 is compared with the reference value when the probe electrode 4 descends and the tip of the probe electrode 4 comes into contact with the seal material. The value increases by several tens of mV. When the probe electrode 4 further descends and comes into contact with the liquid surface inside the container,
The output voltage 33 of the electrostatic capacitance detection circuit is increased by several tens of mV in analog value as compared with the case of contact with the sealing material. Then, the comparison / determination unit 26U compares only the change when the tip of the probe 4 comes into contact with the liquid surface with the written program by comparing the data in the data latch unit 26R and the data in the RAM 26T in synchronization with the clock signal 26V. The liquid level detection signal 39 (FIG. 16) is detected and generated.

Next, when there is no sealant on the upper part of the container, the output voltage 33 of the electrostatic capacity detection circuit increases by several tens of mV compared with the reference value only when the probe 4 descends and comes into contact with the liquid surface in the container. The comparison / determination unit 26U detects only a change when the tip of the probe electrode 4 comes into contact with the liquid level in the container and generates a liquid level detection signal 39. Also in this embodiment, the sampling arm controller 38 takes in the liquid level detection signal obtained by adding an arbitrary delay time t to the liquid level detection signal 39,
The tip of the probe electrode 4 can surely enter the liquid surface of the sample in the container.

〔The invention's effect〕

According to the present invention, it is possible to achieve the above-described object of the invention in the case of detecting a liquid level by detecting a change in capacitance detected by a probe when a liquid is dispensed by the probe.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram for explaining a sampling mechanism in one embodiment of the present invention, FIG. 2 is a diagram showing an appearance of one embodiment of the present invention, and FIG. 3 is a liquid in the embodiment of FIG. FIG. 4 is a block diagram showing a circuit configuration of the surface detection means, FIG. 4 is a diagram for explaining a change in electrostatic capacitance value when the container is provided with a membrane lid, and FIG. 5 is a diagram when performing the measurement as shown in FIG. For explaining the operation of the probe of FIG. 6, FIG. 6 is a diagram showing the configuration of the electrostatic capacitance detection circuit, FIG. 7 is a signal waveform diagram in the circuit of FIG.
FIG. 8 is a configuration diagram of a liquid level detection determination circuit which is operated when the container is provided with a membrane lid, FIG. 9 is a signal waveform diagram in the circuit of FIG. 8, and FIG. 10 is a circuit of FIG. 11 is a flow chart showing the operation of FIG. 11, FIG. 11 is a view for explaining the change in the capacitance value when the container does not have a membrane lid, and FIG. 12 is a view for explaining the operation of the probe when performing the measurement shown in FIG. Figure to
FIG. 13 is a block diagram of a liquid level detection determination circuit which is operated when the container does not have a membrane lid, FIG. 14 is a signal waveform diagram in the circuit of FIG. 13, and FIG. 15 is another embodiment of the present invention. FIG. 16 is a configuration diagram of the liquid level detection determination circuit in the example, and FIG. 16 is a signal waveform diagram in the circuit of FIG. 2 ... Reaction disk, 4 ... Probe electrode, 6 ... Reagent container,
7 ... Sample container, 9 ... Metal plate electrode, 14 ... Detection plate, 15 ...
Film, 19 ... Photo interrupter, 22 ... Oscillation circuit, 25 ... Capacitance detection circuit, 26 ... Liquid level detection determination circuit.

Claims (3)

[Claims] 1. A probe for dispensing a liquid from a liquid containing container containing a sample or reagent solution to a reaction container is used as a liquid level detecting electrode, and static electricity is produced when the probe comes into contact with the liquid in the liquid containing container. In an analyzer configured to detect a liquid surface by a change in capacitance, the probe is provided with an oscillating section for giving a high frequency signal, and when the probe descends and approaches the upper end of the liquid container, An analyzer having a liquid level detection function, comprising an oscillation control unit that starts high frequency oscillation from an oscillation unit and stops the high frequency oscillation when the probe reaches the liquid level. 2. The apparatus according to claim 1, wherein a container having a membrane lid on the upper end is provided as the liquid container, and the tip of the probe is located between the membrane lid and the liquid surface. And an electrostatic capacitance value when the tip of the probe comes into contact with the liquid surface. An analyzer having a liquid level detecting function. 3. An electrostatic discharge when a probe for dispensing a liquid from a liquid container containing a sample or reagent solution to a reaction container is used as a liquid level detecting electrode, and the probe comes into contact with the liquid in the liquid container. In an analyzer configured to detect a liquid surface by a change in capacity, an electrode plate on which a plurality of liquid storage containers can be placed is provided, and a reagent liquid container provided with a membrane lid on the electrode plate and a membrane lid are not provided. When a sample container is placed and a reagent solution and a sample are dispensed to the reaction container by the same probe, the probe detects the reagent liquid surface in the reagent liquid container and the sample liquid surface in the sample container. An analyzer having a liquid level detection function, which is configured as described above.